Genomic resources of two aquatic Lepidoptera, Elophila obliteralis and Hyposmocoma kahamanoa, reveal similarities with Trichoptera in amino acid composition of major silk genes.

While most species of butterflies and moths (Lepidoptera) have entirely terrestrial life histories, ∼0.5% of the described species are known to have an aquatic larval stage. Larvae of aquatic Lepidoptera are similar to caddisflies (Trichoptera) in that they use silk to anchor themselves to underwater substrates or to build protective cases. However, the physical properties and genetic elements of silks in aquatic Lepidoptera remain unstudied, as most research on lepidopteran silk has focused on the commercially important silkworm, Bombyx mori. Here, we provide high-quality PacBio HiFi genome assemblies of two distantly-related aquatic Lepidoptera species (Elophila obliteralis (Pyraloidea: Crambidae) and Hyposmocoma kahamanoa (Gelechioidea: Cosmopterigidae)). As a step toward understanding the evolution of underwater silk in aquatic Lepidoptera, we used our two genome assemblies and compared them to published genetic data of aquatic and terrestrial Lepidoptera. Sequences of the primary silk protein, h-fibroin in aquatic moths have conserved termini and share a basic motif structure with terrestrial Lepidoptera. However, these sequences were similar to aquatic Trichoptera in that the percentage of positively and negatively charged amino acids was much higher than in terrestrial Lepidoptera, indicating a possible adaptation of silks to aquatic environments.

New arthropod-Podostemaceae associations in Central and South America.

Podostemaceae are a unique family of aquatic angiosperms found in river rapids and waterfalls throughout southern Asia, Africa, and the Americas. Podostemaceae are understudied, and consequently, the arthropods associated with these plants are not well known. We sought to expand knowledge of arthropod-Podostemaceae associations to better understand the impact of these plants on aquatic ecosystems and biodiversity. We examined samples of Podostemaceae collected between 1998 and 2007 from Brazil, Costa Rica, Suriname, and Venezuela for arthropods even though these samples were not collected with the intent to investigate arthropod-Podostemaceae associations. We examined 15 samples of Podostemaceae, including 10 species never evaluated for arthropod associations, and found over 9000 arthropods representing 12 different orders. The most abundant orders were Diptera (77.88%), Trichoptera (12.90%), Coleoptera (3.35%), and Lepidoptera (2.42%). We found several arthropods not previously reported from Podostemaceae, including Collembola and Acari, documented several instances of insects boring into plant tissues, and provide the first report of an insect-induced gall on Ceratolacispedunculatum C.T. Philbrick, Novelo & Irgang.